[@Nyahahameha] Kido without incantations is just weaker, not more difficult.

I think in your character's case, they'll probably use Kido without incantations at first, but then develop a string instrument to replace incantations with something to get them more oomph. I just suggested that since that sort of gimmick sounds like a release already, but I suppose it's not too different from having ointment stored inside of the handle of your zanpakuto.

Given where we are in the story, this is a ripe opportunity for your character to develop this sort of gimmick.

We haven't been suuuuper consistent with that rule too, but it will probably start mattering soon enough.